Low computational complexity of resource allocation for the MIMO-OFDMA system

In this paper, we investigate the resource allocation of the multi-input multi-output and orthogonal frequency division multiple access (MIMO-OFDMA) system when SNR is high, including subcarrier allocation and power allocation. Previous researchers mainly concentrate on increasing the system´s capacity, but they don´t care about the computational cost for using the optimal solutions. In this paper, we propose a new method to reduce the computational complexity. At first, we combine with the subcarrier chunk scheduling and a mathematical simplification criterion to alleviate the complexity of subcarrier allocation. Then we use a modified iterative water-filling to decrease the computational complexity of the power allocation. In order to limit the minimum and maximum resources allocated to the users, fairness constraint is employed. Simulation results show that our algorithm can achieve very close system capacity performance of the optimal performance in the MIMO-OFDMA system. It can also be seen from the results that our algorithm can work very well in user fairness.